How quick (default time) does a router using ospf react to a perceived topology change? Is there a gap between the point in time it notices a change, and the point in time where it multicasts an updated LSA to it's neighbors? I suspect a basic security problem exists if you could create a script on an ospf router that flips interfaces off/on randomly, and faster than the router updates an LSA, making a network that's constantly flooded with LSU messages.